During the fabrication of semiconductor devices such as integrated circuits (ICs) from semiconductor wafers, debris and residues may be produced from one or more fabrication processes performed on the wafer. These byproducts of fabrication may become transient particles on the surface of the devices being fabricated, and may render these devices semi or non-functional. In order to remove some of these transient particles, one or more wafer cleaning processes may be incorporated as part of the semiconductor device fabrication.
One particular type of wafer cleaning process is ultrasonic or megasonic cleaning. This particular type of cleaning process typically utilizes a liquid medium deposited on a wafer surface, which is subjected to mechanical pressure waves, typically in the form of ultrasonic or megasonic waves. These waves create cavitation and cavitation implosions in the liquid medium, which may cause particles to be dislodged from a wafer surface. However, this particular type of cleaning process may be limited in the size of debris particles that it may remove, and additionally, use of this process may result in damage to a wafer surface.
Laser cleaning is another cleaning process that may be used to remove particles of sizes smaller than those that may be removed by use of ultrasonic or megasonic cleaning, for example. Dry laser cleaning is one particular type of laser cleaning, wherein a laser beam is directed towards a dry wafer surface, typically directed towards transient particles on the surface of the wafer. If the laser is discharged into a transient particle, energy from the laser beam may be dissipated in the particle, causing the physical bond, or particle/wafer contact interface, to be broken. However, dry laser cleaning may be difficult to control, and may result in damage to a wafer surface if the laser is discharged into the wafer surface. A need, therefore, exists for a method and apparatus for particle removal, which addresses at least some of these limitations.